We propose to establish a model population-based dementia and Alzheimer's disease (SDAT) register in east central Iowa, using the facilities and resources of the existing State Health Registry of Iowa, which currently registers cancer and birth defects. Features of this proposed registry include abstraction of hospital and regional tertiary behavioral neurology clinical records and the maximal exploitation of existing medical care records, including those of Medicaid, Medicare, the Iowa Hospital Association, the Iowa Foundation for Medical Care (PRO), the local Area Agencies on Aging, vital records, SDAT support groups and related helping organizations. Criteria for case entry are clearly specified. Several studies are proposed to evaluate and improve the quality of community-wide dementia and SDAT diagnosis and registration including a) many quality control measures in registry management, b) the use of a large NIA-sponsored cohort study of the rural elderly to examine the process and features of coming to dementia registration, c) an evaluative study of identifying dementia in chronic care institutions, d) a pilot study of physician educational intervention for improving dementia diagnosis and reporting, and e) the establishment of sentinel physicians for dementia and SDAT surveillance. We expect this project to develop optimal ways to conduct community-based dementia registration for purposes of epidemiological and clinical research and other health care applications.